Preserving seasoning flavour profiles during the manufacturing of food-seasoning sheets

ABSTRACT

A method and an installation are provided for preserving desired seasoning flavour profiles during the manufacturing of food-seasoning sheets. The method includes the steps of; laying a thin layer of adhesive on a base sheet; removing air from the adhesive prior to the step of laying; reducing free moisture from the adhesive during the step of laying, and depositing food-seasoning ingredients onto the thin layer of adhesive. The installation for manufacturing food-seasoning sheets includes an adhesive dispenser having a reservoir and a delivery slot communicating with the reservoir for dispensing adhesive. The dispenser has a heating element mounted thereto for heating the adhesive. The adhesive is made under a partial vacuum and it is conveyed to the dispenser in a partial vacuum.

This is a divisional application of application Ser. No. 13/137,155filed Jul. 25, 2011

FIELD OF THE INVENTION

This invention pertains to the manufacturing of food-seasoning sheets,and more particularly, it pertains to the calibration of ingredients infood-seasoning sheets.

BACKGROUND OF THE INVENTION

Packaging material for curing or marinating fresh food during storagehas been part of the art for some time U.S. Pat. No. 6,623,773 forexample, issued to Mr. Hans J. Meier, one of the inventors of theinstant application, has been granted on Sep. 23, 2003. This documentexplains the composition of food-seasoning sheet products.

Other known documents describing similar sheet materials include:

-   U.S. Pat. No. 5,705,214 issued to T. Ito et al., on Jan. 6, 1998;-   CA Patent 2,007,522 issued to T. Ito, et al., on Mar. 14, 2000;-   US publ. 2009/0274799 published by R. V. Lee et al., on Nov. 5,    2009.

Referring back to the Meier patent, U.S. Pat. No. 6,623,773, which isincorporated herein by reference, it is explained therein that thecalibration of seasoning ingredients bonded to a food-seasoning sheet isclosely depending on the amount of adhesive that has been applied to thesheet. We might add that the calibration of seasoning ingredients in afood-seasoning sheet is also closely depending on the condition of theadhesive when seasoning ingredients are deposited over the sheet.

Spice products for example, are granular or powdery in nature and theiradhesion to a food-seasoning sheet depends on the portion of eachgranule that sinks into the layer of adhesive. The thickness and surfacetension of the adhesive layer are contributing factors in the ability toretain the spice product to a food-seasoning sheet. When the layer ofadhesive is too shallow, the surface of the adhesive tends to dry up andto form a shell that does not retain powdery spice materials. A thickerlayer of adhesive tends to remain more fluid and wet, and to completelyencapsulate and/or dissolve spice particles. In some instances, athicker layer of adhesive may hinder the release of the spice particlesfrom the sheet and into the food to be marinated. Furthermore, the airand water content of the adhesive are contributing factors to cause moreor less absorption of the seasoning ingredients into the adhesive and tomodify the potency of these ingredients. Therefore, both the thicknessof adhesive and the wetness of this adhesive are important factors toconsider in the manufacturing a high quality food-seasoning sheets.

For example, it is well known that HVP's (hydrolyzed vegetable proteins)and sucrose are very moisture-sensitive elements that have the abilityto extract moisture from a substrate. This makes these elements verydifficult to work with without losing their effectiveness.

The type of adhesive that is used in these applications has a viscousstructure. When such an adhesive is discharged from a slot die forexample, it may have a foamy texture with air entrapped in it. When airis released from the adhesive, the final volume of adhesive remaining onthe sheet is less than the amount calibrated through the slot die. Also,when air is released from the surface of the adhesive, it promotes afaster drying of the surface. Consequently, the wetness of the adhesiveapplied to a food-seasoning sheet also depends on the air content in theadhesive exiting the slot die. Similarly, the free moisture present inthe adhesive tends to dissolve the food-seasoning ingredients into theadhesive and/or into one another and to reduce the potency of theseasoning ingredients.

Because of these factors, basically, it has been difficult in the pastto precisely calibrated the amount of adhesive delivered onto afood-seasoning sheet. Therefore, there exists a need for preciselycontrolling the amount of adhesive that is laid on a food-seasoningsheet and there also exists a need for controlling the amount of air andfree moisture present in that adhesive.

SUMMARY OF THE INVENTION

In the present invention, there is provided an installation fordispensing adhesive onto a moving base sheet, wherein the amount ofadhesive laid on a base sheet is precisely calibrated in a very thinlayer. Air and free moisture are removed from the adhesive before theadhesive is dispensed onto the base sheet. The adhesive is in a morefavourable state for receiving food-seasoning products thereon.

In a first aspect of the present invention, there is provided a methodfor preventing a dissolution of food-seasoning ingredients into theadhesive. This method comprises the steps of

-   -   laying a thin layer of adhesive on a base sheet;    -   removing air from the adhesive prior to the step of laying;    -   reducing free moisture from the adhesive during the step of        laying, and    -   depositing food-seasoning ingredients onto the layer of        adhesive.

The removing of air and free moisture from the adhesive has been devisedprimarily for obtaining a better dispensing of the adhesive on a basesheet. Because the adhesive that is used in the method according to thepresent invention has less air entrapped in it and contains less freemoisture, this adhesive can be applied in very thin layers and can beapplied with clean edges and clean breaks.

In addition to making the adhesive easy to apply on a base sheet, i.e.clean edges and clean breaks, a new and unexpected advantage has beenobtained. It is believed that because of the low water activity and theextremely thin application of the adhesive, there is minimal (if any)dissolving of potentially soluble food-seasoning ingredients into theadhesive and/or into one another. The low water activity means thatthere is little free water available to dissolve anything. The thinapplication and the scarcity of air speed up the drying process tofurther reduce free moisture. As a result of minimal dissolving, thereis nothing to diminish, mask or alter the seasoning flavour profileselected. The flavour profiles desired are more easily obtained andpreserved. The flavour profiles desired are more precisely duplicatedfrom one order to the next.

In another aspect of the present invention, there is provided aninstallation for manufacturing food-seasoning sheets having a layer ofadhesive laid onto on a base sheet and food-seasoning ingredients bondedto the layer of adhesive. This installation includes a first reservoirfor making liquid adhesive therein. The installation also has a liquidadhesive dispenser having a slot die and a second reservoir in the slotdie for receiving the liquid adhesive from the first reservoir; and adelivery slot in the slot die communicating with the second reservoirfor dispensing the liquid adhesive onto the base sheet. There is alsoprovided a pump and a piping system for pumping the liquid adhesive fromthe first reservoir to the second reservoir in an air free environment.A spice dispenser is included for dispensing spice product over theliquid adhesive on the base sheet. In this installation, the firstreservoir has a mixer and a vacuum pump connected to it for generating apartial vacuum in the first reservoir when the first reservoir containsthe liquid adhesive, and for removing air from the liquid adhesive priorto delivering the liquid adhesive to the second reservoir. As a result,the liquid adhesive laid on the base sheet has less air entrapped in itsuch that it is more easily applied in a very thin layer.

In yet another aspect of the installation according to the presentinvention, there is provided a heating element mounted in or to the slotdie for heating the adhesive as it is dispensed onto the base sheet. Theheating of the adhesive promotes the evaporation of free moisture fromthe adhesive and the release of air entrapped in the adhesive. Theadhesive is easily applied in thin layers with clean edges and breaks.

In yet a further aspect of the installation according to the presentinvention, there is provided a vacuum box mounted under the deliveryslot of the slot die for removing air from the base sheet and from theadhesive when the adhesive is laid on the base sheet.

In yet another aspect of the installation according to the presentinvention, there is provided a system for winding the base sheet afterspice products have been dispensed on it, and a monitoring and controlsystem for setting and controlling a tension in the base sheet during awinding of the base sheet, for preventing damage to the food-seasoningsheets during storage and transport to a client.

In yet a further aspect of the installation according to the presentinvention, a template is mounted in the slot die. The template has adado edge extending in the delivery slot for locally obstructing a flowof adhesive through the delivery slot and for creating margins free ofadhesive on the base sheet.

This brief summary has been provided so that the nature of the inventionmay be understood quickly. A more complete understanding of theinvention can be obtained by reference to the following detaileddescription of the preferred embodiment thereof in connection with theattached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

A preferred embodiment of the present invention is illustrated in theaccompanying drawings, in which like numerals denote like partsthroughout the several views, and in which:

FIG. 1 is a schematic representation of an adhesive dispenser and aspice dispenser in an installation for manufacturing food-seasoningsheets;

FIG. 2 is a cutaway perspective view of the slot die in the adhesivedispenser;

FIG. 3 is a cross-section view of the slot die as seen substantiallyalong lines 3-3 in FIG. 2;

FIG. 4 is a cutaway view of a reservoir for making adhesive to bedelivered to the adhesive dispenser of FIGS. 2 and 3;

FIG. 5 is a block diagram of the operation and control equipmentincluded in the installation for manufacturing food-seasoning sheets.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring firstly to FIG. 1, the manufacturing of a food-seasoningsheets in the installation according to the preferred embodiment will beexplained in a general manner. As a base, a film 20 of plastic materialis supplied to the adhesive dispenser 22 from a roll of film for example(not shown). The film 20 can be made of polyethylene for example orother sheet material, but this is not the focus of the presentinvention.

The film 20 is wrapped over a slot die mandrel 24 which is mounted closeto a slot die 26. The slot die 26 has a delivery slot 28 facing the slotdie mandrel 24. The film 20 passes in a small gap 30 between thedelivery slot 28 of the slot die 26 and the slot die mandrel 24.

Adhesive is delivered under pressure from a reservoir (described later)to the slot die 26, via the inlet tubing 32. The inlet tubing 32 has aconnection to a piping system represented by a dash line 34. Theadhesive is pumped through the body of a pull-back valve 36 and into theslot die 26. The operation of the pull-back valve 36 and the slot die 26will also be described later.

The adhesive-covered sheet 40 is then passed under a spice dispenser 42where a calibrated amount of spice product is delivered on the top ofthe sheet. The spice product is delivered over the wet adhesive, to bondto the adhesive. The spice dispenser 42 is located at a minimum distancefrom the adhesive dispenser 22 to minimize the drying of the adhesiveprior to dispensing the spice product on the sheet 40. The spice-coveredsheet is then allowed to dry on the run to a winder (not shown), whereit is wound on a storage roll.

Although the words “spice” and “spice product” are used herein, thesewords are used for convenience only and should not be limiting in theinterpretation of the present invention. The spice dispenser 42 may beused to deliver granular food products, salt, pepper, sugar, chocolate,nuts, fruits, spices, preservatives, seasoning formulations,anti-microbial compositions, medicinal products or any combination ofthese substances, or any product of that nature.

The operation of the spice dispenser 42 is not described in detailherein because it is not the focus of the present invention. In thepreferred installation, the calibration of the amount of spice productdelivered per unit of surface of film 40 over time is done by weight andthis is controlled by computer and load cells 44 mounted under the baseof the spice dispenser 42, and a speed sensor (described later) readingthe speed of the slot die mandrel 24 on the adhesive dispenser 22 forexample.

Referring now to FIGS. 2 and 3, the structure and operation of theadhesive dispenser 22 will be described. In FIG. 2, the slot die 26 isshown with its top half 50 in a cutaway view. The pull-back valve 36 isconnected to an opening 52 in the top half 50. This opening 52communicates with a reservoir 54 in the bottom half 56 of the slot die26. The reservoir 54 can be seen in the cross-section view of the slotdie 26 in FIG. 3. The reservoir 54 communicates with the delivery slot28.

The reservoir 54 further has two vent holes 58 along a top portionthereof to evacuate air entrapped in it. The vent holes 58 have adimension to allow air to escape out, but to restrict the flow ofadhesive there through.

A flat template 60 is mounted between the top and bottom halves 50, 56of the slot die 26 and over the reservoir 54. The thickness of thetemplate 60 is a same thickness as the gap of the delivery slot 28 inthe slot die 26. The template 60 has a dado edge with fingers 62 andrecesses 64. The fingers 62 block portions of the slot 28 of the diewhile the recesses 64 allow adhesive to flow though other portions ofthe slot 28 of the die. The local blocking of the slot 28 of the slotdie 26 at the fingers 62 causes the formation of clean margins 70 alongthe adhesive-covered sheet 40 so as to define strips 72 of adhesive onthe adhesive-covered sheet 40, and margins 70 free of adhesive.

The operation of the pull-back valve 36 creates a partial vacuum in thereservoir 54 and pulls back the adhesive upward in the conduit 52. Thepull-back valve 36 comprises a spool 80 that is movable in a valve body82, under the action of a pneumatic actuator 84. The details of thespool 80, the valve body 82 and the actuator 84 are not provided hereinbecause these details are not the focus of the present invention and areknown to those skilled in the art. The valve 36 is basically a two-wayvalve.

The operation of the pull-back valve 36 causes interruptions in the flowof adhesive through the slot 28 of the slot die 26. The operation of thepull-back valve 36 creates interruptions in the delivery of adhesive tothe adhesive-covered sheet 40 when the sheet 20 is moving in front ofthe delivery slot 28, thereby causing breaks 90 in the strips ofadhesive 72.

The slot die 26 is separable in two halves 50, 56 and the template 60 isremovably mounted between both halves. Different templates 60 may beused with different dado edges to define more or less margins 70 andmargin widths. The operation of the pull-back valve 36 may be controlledby a timer and a programmable controller or other computer to vary thefrequency and length of the breaks 90.

These clean margins 70 and breaks 90 free of adhesive are useful formanufacturing foldable food-seasoning sheet products such as envelopesand bags for examples. The clean margins and breaks provide cleansurfaces that can be bonded to each other using heat-sealing equipmentfor example.

The stroke length of the spool 80 of the pull-back valve 36 is selectedso that air does not get into the reservoir 54. The stroke length isselected to break the flow of adhesive through the slot 28 of the die26, without introducing air in the slot 28.

The movement of the valve spool 80 of the pull-back valve 36 and of theresulting movement of the adhesive inside the reservoir 54 associatedwith the partial vacuum that is created inside the reservoir 54 causes acertain amount of air to be released from the adhesive inside thereservoir 54 and to be evacuated through the vent holes 58.

A heating element 92 and a thermocouple 94 are mounted in or to the slotdie 26. The exact location of the heating element and the thermocouplecan vary from the illustration in FIG. 3, according to the choice of thedesigner. This heating element 92 and thermocouple 94 are used tocontrol the temperature of the adhesive exiting the slot die 26. It hasbeen found that a controlled heating of the adhesive prior to deliverythrough the slot die 26 improve trailing edge quality and uniformity inthe adhesive layer. It also has been found that a heating of theadhesive helps to release air entrapped in the adhesive and from thereservoir 54. It has further been found that the heating of the adhesivehelps to reduce free moisture in the adhesive being delivered onto thefilm 20. Reduced amounts of air and free moisture in the adhesive havebeen found to yield a better quality food-seasoning sheets with lessdissolving of the food-seasoning ingredients.

A vacuum box 100 is also provided immediately under the gap 30 and thedelivery slot 28. The vacuum box 100 is open at the top as can be seenin FIG. 3, with an opening facing the surface of the slot die mandrel 24immediately below the delivery slot 28. A partial vacuum is applied intothe box 100 by a vacuum pump 146 as illustrated in FIG. 5 for example,and an air flow is drawn therein from the surface of the slot diemandrel 24, to remove air from the surface of film 20 immediately beforeadhesive is deposited to the film 20. As may be appreciated, the vacuumbox also has the ability to remove air from the lower laminae ofadhesive exiting the slot 28 of the die.

The removal of air from the film 20 and from the lower laminae ofadhesive ensures that less air is be trapped under and into theadhesive. As may be appreciated, this removal of air reduces the amountof air permeating through the layer of adhesive on the adhesive-coveredsheet 40.

Referring now to FIG. 4, there is illustrated therein a reservoir 110for making and mixing a batch of adhesive, for use in the slot die 26.The adhesive is pumped from the reservoir 110 though the piping system34 shown in FIG. 1. The reservoir 110 is of a type that can behermetically sealed. The reservoir 110 has a mixer 112 mounted therein.The reservoir 110 also has a tubing 114 connected to a top part thereofat connection 116 for example. The tubing 114 is connected to a vacuumpump 118.

In use, a batch of adhesive is prepared and mixed under at least apartial vacuum so that a minimum amount of air is entrapped in theadhesive. The adhesive is transferred to the slot die 26 and enters theslot die 26 under pressure from a pump 120 and tubing 34. Both the pump120 and tubing 34 are hermetically sealed as it is customary withequipment of that nature. The adhesive being pumped is not exposed toair between the reservoir 110 and the slot die 26.

Referring now to FIG. 5, there is illustrated therein a block diagram ofthe equipment included in the preferred installation for manufacturingfood-seasoning sheets. The installation is controlled by a programmablelogic controller (PLC) 130 with motion controllers. A touch-screen inputdevice 132 is used to enter settings for different food-seasoningprofiles.

Servo drives 134, encoders 136 and feedback loops 138 are used forcontrolling the speed of each function driver.

Referring to individual function drivers, the adhesive delivery pump 120is connected to the adhesive reservoir 110. The reservoir 110 as shownin FIG. 5 is a same reservoir as the mixing reservoir shown in FIG. 4.However, in some installations, two reservoirs may be used; one forbatch mixing the adhesive and one for delivering the adhesive to theslot die 26 in a continuous mode.

The adhesive delivery pump 120 is a volume-controllable pump and itsdelivery volume is controlled in relation to film speed measured at slotdie mandrel 24, in a control feedback loop 140. The adhesive deliverypump 120 is programmable to set precise coat weight or thickness.

The delivery of spice product from the spice hopper 42 to the web isalso controlled in relation with the speed of the slot die mandrel 24,by means of a feedback loop 142 between the spice delivery mandrel 150and the slot die mandrel 24.

The spice application is based on a loss-of-weight feeding system,including load cells 44 under the spice hopper 42, and a first summingmodule 152 reading the load cells 44. The speed of the servo motor 150on the spice mandrel 150′ is controlled by weight loss over film speedand recipe request. The location of the spice mandrel 150′ can be seenin FIG. 1.

The film speed and film tension are controlled through a feedback loop154 between a web-unwind roll 156 and a web rewind roll 158. Each of thefilm unwind roll 156 and film rewind roll 158 is driven by a gear box160 and a servo motor 162.

The film speed and film tension are also controlled by measurement ofthe radial strain on a tension roll 164. The tension roll 164 can alsobe seen in FIG. 1. A pair of load cells 44′ are installed on the tensionroll 164 to measure film tension. The signals from these load cells 44′are integrated in a second summing module 166, and are used to adjustspeed and torque of both the film unwind roll 156 and film rewind roll158. Torque is recipe-dependent and is controlled especially forpreventing product damage on roll-up of the coated film 40.

The installation according to the preferred embodiment for manufacturingfood-seasoning sheets has the ability to precisely control the thicknessof the adhesive layer and the volume of food-seasoning ingredientsdeposited on the film surface. The preferred installation also has theability to control film tension at roll-up. Further, the preferredinstallation has the ability to control free moisture and air content inthe adhesive. As a result, a better calibration of the food-seasoningingredients is obtained.

The preferred installation has limited absorption of the food-seasoningelements into the adhesive or vice-versa, or into one another. Thefood-seasoning elements keep their maximum potency.

As to other manner of usage and operation of the manufacturing offood-seasoning sheets, the same should be apparent from the abovedescription and accompanying drawings, and accordingly, furtherdiscussion relative to these aspects is deemed unnecessary.

What is claimed is:
 1. In a manufacturing of a food-seasoning sheetcomprising a base sheet, a layer of adhesive laid on said base sheet andfood-seasoning ingredients bonded to said layer of adhesive, the methodof preventing a dissolution of said food-seasoning ingredients into saidadhesive, comprising the steps of: receiving a volume of said adhesivein a slot die; heating said volume of said adhesive and removing air andfree moisture from said volume of said adhesive; laying a thin layer ofsaid adhesive on said base sheet; and depositing food-seasoningingredients onto said layer of said adhesive.
 2. The method as claimedin claim 1, wherein said step of removing air from said adhesivecomprises the steps of: removing air from said adhesive during a makingof said adhesive in a first location, and pumping said adhesive to anadhesive dispenser in an air free environment to a second locationdifferent from said first location.
 3. The method as claimed in claim 1,wherein said step of laying comprises the step of controlling a volumeof said adhesive according to a speed of said base sheet when saidadhesive is delivered to said base sheet.
 4. The method as claimed inclaim 3, further comprising the step of removing air from said adhesiveand from said base sheet when said adhesive is delivered to said basesheet.
 5. The method as claimed in claim 4, further including the stepof periodically creating a partial vacuum in said slot die.